The IV Corps (Vietnamese: Quân đoàn IV) was a corps of the Army of the Republic of Vietnam (ARVN), the army of the nation state of South Vietnam that existed from 1955 to 1975. It was one of four corps in the ARVN, and it oversaw the Mekong Delta region of the country. On 3 May 1972 Corps' commander Lieutenant General Ngô Quang Trưởng, was appointed commander of I Corps and Major General Nguyễn Vĩnh Nghi assumed command of the Corps.